Humidifier



p 22, 1964 I w. HLWENTLIING ET Al. 3,149,626.

v v I HUMIDIFIER Filed uayzo, 1963 2 Sheefcs-Sheet 1 lul E 6 'mm.

l Milk a INVENTORS 80 WILLIAM HLWENTLING a BY CLARENCE e. NENADAL ATTORNEY P 22, 1964 w. H. WENTLING ETAL 3,149,626.

HUMIDiFIER Filed May 20, 1963 2 Sheets-Sheet 2 INVENTORS WILLIAM H.WENTLING 8: BY CLARENCE G.NENADAL ATTORNEYS United States Patent 3,149,626 HUMIDH ER William H. Wentling, Dayton, and Clarence G. Nenadal,

Cleveland, Ohio, assignors to The Lau Blower Company, Dayton, Ohio, a corporation of Ohio Filed May 20, 1963, Ser. No. 281,508 14 Claims. (Cl. 126-113) This invention relates to a device for increasing the moisture content of air, and more particularly to a humidifier adapted for use with domestic hot air furnaces or the like.

Humidifiers for domestic use can be broadly grouped as the evaporation plate type or the power operated type. In the former, stationary absorbent plates of asbestos or other equivalent materials are supported above a reservoir pan with a portion of each plate submerged so that the entire surface area thereof is wetted. As the warmed air from the associated furnace flows over these surfaces, the moisture is evaporated, and thus the moisture of the air is increased. The power type humidifier generally includes a fan or the like for forcing air over or through an evaporation media, such as a drum or belt, which has a portion thereof continuously moved through a water reservoir. The present invention is directed to a humidifier of this latter type.

An important object of this invention is to provide an automatic power operated humidifier unit adapted to be mounted on a domestic heating unit or the like without major modification of the heating unit, and particularly to provide such a unit which. .is compact in size and highly efiicient in operation so that it is highly suitable for use with most modern furnaces.

Another object of this invention is to provide an improved power operated humidifier of the aforesaid type which has a minimum of moving components for increased dependability and decreased cost, and particularly to provide a unit wherein a single motor positively drives at their required speeds both the fan and drum on which the evaporation media is mounted.

A further object of this invention is to provide a humidifier unit which can be easily assembled and dis assembled for cleaning, and specifically to provide a unit of this type with an evaporator drum which offers a minimum of resistance to air flow through the sides thereof and which utilizes resilient and highly porous evaporation media capable of being cleaned by any conventional expedient.

Other objects and advantages of the invention will be apparent from the following description, the accompanying drawings and the appended claims.

In the drawings FIG. 1 is a side view, partially in section, of the humidifier unit mounted on a vertical wall of a hot air furnace or the like;

FIG. 2 is a sectional view taken essentially along the line 2-2 of FIG. 1;

FIG. 3 is a sectional'view of the speed reduction unit taken essentially along the line 3--3 of FIG. 2;

FIG. 4 is a sectional view of the humidifier unit taken along the line 44 of FIG. 1;

FIG. 5 is an enlarged sectional view of the flow control valve; and

FIG. 6 is a greatly enlarged fragment of the evaporation media.

Referring to the drawings wherein a preferred embodiment of the invention is shown, FIG. 1 illustrates a humidifier unit 10 including the rectangular upper and lower housing members 11 and 12 which support all of the components of the unit. The members 11 and 12 are secured together by suitable screws 13 which extend the drive shaft 40.

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17 or the like so that they can be easily separated during assembly and disassembly of the unit for cleaning. Keyhole slots 20 are provided in the upper corners of the upper housing member 11 and in the lower corners of the lower housing member 12, and screws 21 extend therethrough to secure the unit 19 releasably to the vertical wall 22 of the furnace or air duct. By merely loosening the screws 21 and slightly raising the housing members 11 and 12, the entire unit 10 can be removed from the wall 22.

The upper housing 11 supports substantially all of the movable components of the unit including the evaporator drum 25, the fan 26, the speed reduction unit 27, and the drive motor 28, and thus all of these components can be removed with housing member 11 from the unit 1i! as a separate sub-assembly. The reduction unit 27 is mounted securely on the outside surface 31 of the upper housing member 11 by the four studs 32, which are internally threaded for receiving screws 33 to secure one end of each stud to the surface 31, as shown in FIG.

housing on either side of the motor drive shaft 40. The

drive shaft 4%, as shown in FIG. 3, projects completely through the speed reduction unit 27, and has the small diameter pinion 41 rigidly secured thereon for meshing engagement with the larger gear 42 mounted in the housing 36. The small pinion 43 is secured to the gear 42 for rotation therewith to efiect rotation of the larger gear 44, which has another small pinion 45 secured rigidly thereto for transferring the rotary motion to the output gear 47. The gears and pinion are preferably formed of a corrosion resistant and noiseless material, such as the material'sold under the trade name Delrin. All of these gears and pinions are rotatably supported in the housing 36 and have appropriate pitch diameters for substantially reducing the speed of the output gear 47 with respect to the drive shaft 40. The number and size of the gears and pinions are dictated by the input and output speed, and thus it is within the scope of the invention to vary the number and size of gears and pinions to obtain the desired output speed. Moreover the unit 27 and motor 28 may be interconnected in many different manners.

The tubular output shaft 50 is secured rigidly to the output gear 47 and is consequently also driven in the same direction as and at a speed substantially less than It is also within the scope of this invention to provide a gear arrangement for rotating the shaft 40 and 50 in opposite directions. The shaft 50 is supported for rotation in the horizontally extending boss 51 secured on the cover plate 37 by the bearing 52, and the felt oiler 54 supplies lubricant therebetweenfor frictionless relative movement between these members.

The drive shaft 40 extends axially through the tubular output shaft 50 without contact therewith so that two distinct speeds are provided at the ends of the shafts which extend through the aperture 55 in the upper housing member 11 to the furnace side of the housing members 11 and 12. As will be described in more detail, the tubular shaft 50 has the evaporator drum 25 secured thereon, and the drive shaft 40 which is supported solely by the usual bearings, not shown, of the motor 28, has a portion which extends axially beyond the tubular shaft 50 so that the Patented Sept. 22., 1964 amaeae fan 26 can be secured thereto for concentric rotation entirely within the evaporator drum 25.

The fan 26 includes a dish-shaped support plate 55 having a central hub 57 secured thereto for mounting on the drive shaft 40. A plurality of fan blades 60 of generally triangular configuration have their bases at secured to the convex side of the plate 55, with the blades being smoothly curved in the direction of rotation for cooperation with the convex side of the plate 55 to pro vide an axial air intake and a radial air discharge. In particular, the fan 26 is similar to that shown and described in the copending United States application of Richard F. Beehler and Stephen F. Murray, Serial No. 76,327, filed December 16, 1960, now Patent No. 3,131,- 236 issued April 28, 1964, for Radial Flow Fan, and as signed to the assignee of this invention, but it is within the scope of this invention to utilize any air moving device which is capable of drawing air axially into the evaporator drum 25 and forcing it outwardly thereof in a radial direction, e.g., a centrifugal blower wheel. The humidifier will operate without the fan 26 by the natural flow of heated air over and through the drum 25, although the vefliciency thereof will be substantially reduced.

The evaporator drum 25 includes a back plate 62 which is secured on the tubular drive shaft 50 by the hub 63 which is rigidly connected to the back plate 62. The periphery of this back plate supports a plurality of U-shaped support brackets 65 each of which has its radially extending ends 66 clamped to the back plate 62 adjacent the step 68 (FIG. 1) therein by metal strips 69 cut from the plate 62 and deformed over the ends 66.

The sleeve or media 70 of porous resilient material is snugly fitted around the brackets 65, and its lowermost portion extends into the reservoir 72 formed on the lower housing member 12, as shown in FIG. 1. The reservoir 72 normally has a preset level of water therein so that the lowermost portion of the sleeve 70 is submerged and the surfaces thereof wetted. As will beseen, the flow of air from the fan Zfi passes around and through the porous sleeve '76 thus evaporating the water on the wetted surface.

A very satisfactory and preferred. material for the sleeve 70 is resilient polyurethane foam approximately one-half inch in thicknessand having a porosity of 8 to 13 pores per lineal inch, with best results being obtained using pores per lineal inch. This'material contains numerous irregularly spaced pores or passages therethrough, and this characteristic provides the sleeve 70 with a relatively large effective surface area to become wetted when the sleeve is submerged in water. Another advantage of this material is that the total space consumed by the sleeve 70 is much less than that ofother materials capable of providing a similar amount of surface area. It is an important feature of the invention that the sleeve be non-absorbent since it is not desired to saturate the sleeve but only to wet the surface area thereof so that air will flow readily therethrough.

As shown in the greatly enlarged view of FIG. 6, this polyurethane foam is composed of uniformly distributed interconnecting strands 70a which form a three-dimensional structure of openings or pores, without a covering membrane or surface of the type often found in other types of foam materials. The random arrangement of the pores eliminatesstraight channels through this material so 'that air flowing therethrough passes around each strand 70a, thus, creating, maximum contact therewith with a minimum of air resistance. Also the flow through the material is uniform throughout so that there is maximum flow therethrough. While the pores are not precisely the same size, they are predominately within a range of similar sizes so that the air flowing through and moisture added thereto is uniform throughout the surface on which water is deposited and evaporated therefrom for maximum efficiency of the unit.

Due to the relatively large and uniformly shaped pores, the lime and salt deposits which gradually build up around the strands 79a increase their diameters at such slow rate with respect to the open pore spaces, that even after an extended period of time, the deposits partially restrict air flow through the media sleeve '70 but do not completely cover or block the pores, so that air continues to flow evenly through the entire sleeve 70, rather than being completely blocked in certain areas as is often the case with closely woven fibers or metallic strands. Thus the useful life of this material is substantially greater than materials previously used, and flow through the material continues to be evenly distributed over the entire surface thereof.

For preferred operation, it is desired that only a portion of the Water which wets the sleeve 7 it be evaporated therefrom so that the deposits caused by evaporation are reduced to a minimum since they will tend to be washed from the sleeve 70 as it passes through the reservoir '72, thercby permitting the unit to operate efiiciently for maximum periods before cleaning is required. Reference is made to the copending US. applications of Warner W. Martin and Clifton D. Sweet, In, Serial No. 175,442, filed February 26, 1962, now abandoned, and Serial No. 253,338, filed February 13, 1963, for Power Humidifiers, both assigned to the assignee of this invention.

Also of importance to the invention is the ability'of this media material to be removed and cleaned by common household detergents and solvents without adverse effect to the" person doingthe cleaning or to the material itself. Since cleaning from time to time is a requirement in order to maintain eiiiciency, it is necessary that the sleeve be easily removed and cleaned in a minimum of time without suffering adverse effects. The polyurethane foam material will withstand temperatures from 250 F. to 40 F. Without substantial adverse eifects, and thus the material can be washed by machine to remove the usual deposits therefrom and increase the operative efliciency of the unit.

To remove the media sleeve 70 from the housing, it is merely necessary to remove the unitltl from the Wall 22, and then detach the upper housing 11 from the lower housing 12. Once this is accomplished, the removal of the sleeve 70 from the support bracket is relatively simple in View of the resilience of the polyurethane, and this resilience also facilitates removal of the salt deposits in the innermost pores since the sleeve can be twisted, stretched, etc.

Appropriate electrical connectors, electrical circuitry, and a source of electrical power, none of which are shown, supply electrical power to the motor 23. Suffice to say, the particular manner in which the power is supplied to the motors is within the ability of one skilled in the art. The unit 10 is to be wired electrically to operate simultaneously with the furnace fan so that the humidifier will be supplied with hot air, and if desired, a humidistat can also be wired in series for more positive control. Similarly, the humidifier could be connected in series to a bonnet thermostat of a gravity furnace.

The reservoir water level control system is illustrated in FIGS. 1, 2 and 5 and includes a float chamber 75 which is formed integrally on the outside of the'lower housing member 12. The aperture 76 in the housing member 12 permits water to flow from this float chamber 75 to the water reservoir 72; A source of water is normally connected to the water level control system through the pipe 77 which is secured to the valve body 80 by the female connection 81. The valve body 80 is in turn securely fastened to the wall of the lowerhousin g member 12 by the nut 83. A longitudinal passageway (FIG. 5) through the valve body 80 terminates at one end in an orifice 86 and has a restriction 87 therein which reduces the force of water pressure flowing therethrough to such an extent that the valve disk 90 can readily control flow from the orifice 86.

The valve disk 90 is composed of rubber, Neoprene or other soft durable material, and is mounted on and rotates with an arm 91 between a closed position wherein it contacts the orifice 86 and prohibits water flow therefrom and an open position where it is spaced from the orifice and permits water to flow therefrom. The arm 91 is rotatably secured by pivot pins 92 to the shroud 93 which is formed integrally with the valve body 80 and extends around three sides thereof. Water spray created as the valve disk 90 is moved to or from the closed position will be directed into the float chamber 75 by the reservoir cover 94, as well as the horizontally extending sides of the shroud 93 thus preventing water from spraying onto the motor 28 or associated electrical apparatus.

A float 95 is secured rigidly to the arm 91 and acts as the water level sensing and actuating means which moves the valve arm 91 and valve disk $1 to maintain the predetermined water level in the reservoir 72. That is, when the water level in float chamber 75 changes, the buoyancy of the float 95 causes it to rise or fall and thereby rotate the arm 91 which, in turn, moves the valve disk 90 with respect to the orifice 86 and thus insures that the level in the chamber 75 will be maintained. Since the aperture 76 interconnects the chamber 75 and the reservoir 72, the former will always maintain the water level in the latter.

A motor cover 101) (FIGS. 1 and 2) encloses the motor 28 and the speed reduction unit 27 to protect these components from damage, as well as to improve the over-all appearance of this otherwise exposed portion of the unit It). The cover 100 has the pins 102 provided near the upper rear edge of the cover 1% for engagement with suitable openings in the flange 1% formed integrally with the housing member 11 to anchor this top portion of the cover in place. The lower skirt portion we of the cover has slots 1616 therein which receive threaded studs 137 on the float chamber 75, and studs 1137 receive nuts 108 for releasably securing the cover 100 in place. A plurality of small openings 109 may be pro vided in the front wall 119 of the cover, as well as the elongated slots 111 in the top 112, to insure air flow with suitable sources of water and electrical power con nected, the drive motor 28 will rotate the fan 26 at a relatively high speed so that it draws air in an axial direction into the evaporation drum 25, and forces it in a radial direction through the sleeve 71). Rotation of the drive shaft 49 also efiects rotation of the tubular output shaft 50 and the evaporator drum 25 in the reservoir 72 at a much slower speed by reason of the gear ratios of the speed reduction unit 27, and thus the entire surface area of the sleeve is wetted. The relative speeds of the drum 25 and the fan 26 are correlated so that the sleeve 70 never becomes completely dried thus minimizing formation of deposits thereon.

As the heated air passes through the numerous pores of the sleeve 70, it evaporates a portion of the moisture on the surfaces of the strands 70a with a resulting increase in the moisture content of the air. The continuous rotation of the drum 25 keeps the sleeve 70 constantly wet, and as a result the usual solids or precipitate which are normally formed thereon are held to a minimum. As the water is evaporated, the level in the reservoir will drop, but any slight drop is sensed by the float 95 which opens the control valve and restores the water level in both the chamber 75 and the reservoir 72.

To clean the sleeve of salts and other usual deposits,

it is merely necessary to stop the motor 28, and loosen d ventional manner, and then the unit is reassembled in the reverse of this sequence.

While the preferred embodiments of the invention utilize a sleeve 70 of polyurethane foam, other materials could be used with the housing structure described herein to obtain satisfactory results. Thus while the use of the polyurethane foam provide a particularly desirable lattice structure of interconnecting strands and pores, the invention contemplates use of foam material formed from other natural or synthetic materials, so long as they substantially provide the aforesaid properties and dimensional requirements.

A completely automatic power operated humidifier has been provided which is capable of adding a substantial amount of moisture to the air being heated by the associated furnace. The unit is simple in design, and therefore dependable in operation and inexpensive to manufacture, and is capable of being assembled and disassembled easily for cleaning so that the owner will be more inclined to clean the unit at regular intervals. The fan 27 is positioned entirely within the evaporator drum 25 so that it does not require additional space, and the unit is particularly adaptable for use in modern heating equipment wherein only minimum space is available. Moreover, both the drum 25 and fan 27 are driven at their appropriate speeds from a single motor, so that'these speeds are always correlated and only one set of electrical controls is required.

While the present invention is shown mounted directly on a hot air furnace, it is possible, without departing from the scope of this invention, to mount the assembly remotely from the furnace plenum and connect it to the furnace by a conventional duct or flexible tubing. It might also be desirable to pass warm air from the furnace through the humidifier and then into the cold air sideof the furnace. Also it should be obvious that any connection between the humidifier and the furnace can also be made between the duct work leading to or from the furnace. Accordingly, when reference is made to a hot air furnace, the ducts leading to and from such furnace, as well as other furnace components are referred to.

It is also contemplated that the unit 10 could be utilized separate and apart from a furnace, for example, as a room humidifier. The unit is completely self-contained and could be used in a room by suitably mounting it and appropriately connecting a source of electrical current thereto. A source of water could be connected to the unit, or it could be adapted for manual filling of the Water reszilvoir since the rate at which Water is consumed is sm While the form of apparatus herein described constitutes a preferred embodiment of this invention, it is to be understood that the invention is not limited to this precise form of apparatus, and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims.

What is claimed is:

1. A humidifier for adding moisture to air being treated by an air conditioning device, comprising a mounting plate adapted to be secured on a wall of the air conditioning device, a drive assembly mounted on one side of said plate and having a pair of coaxial drive shafts extending through an aperture in said plate to the opposite side thereof, one of said drive shafts being driven at a speed substantially slower than the other drive shaft, an evaporator drum mounted on said one shaft on the opposite side of said mounting plate, said drum having open and closed ends and including a resilient and porous evaporator material which defines the side walls of said drum, means defining a reservoir on said opposite side of said mounting plate for enclosing the lower portion of said drum, means for maintaining a predetermined water level in said reservoir to wet said evaporator material when said drum is rotated by said drive assembly, said other drive shaft having a portion extending axially from said one drive shaft, and air moving means mounted on said portion of said drive shaft coaxial with and substantially entirely within said drum for drawing air axially through said open end and forcing it radially through said evaporator material to increase the humidity of the air.

2. A humidifier for adding moisture to air being treated by an air conditioning device, comprising a mounting plate adapted to be secured on a wall of the air conditioning device, a drive assembly mounted on one side of said plate and having a pair of drive shafts extending through said plate to the opposite side thereof, one of said drive shafts being driven at a speed substantially slower than the other drive shaft, an evaporator drum means mounted on said one shaft on the opposite side of said mounting plate, said drum means having open and closed ends and including an evaporator material which defines the side walls of said mounting plate for enclosing the lower portion of said drum means, means to wet said evaporator material when said drum means is rotated by said drive assembly, and air moving means mounted on the other of said drive shafts substantially entirely Within said drum means for forcing air axially through said open end and over the surface of said evaporator material to increase the humidity of the air.

3. A compact humidifier unit adapted to be mounted on the Wall of a hot air furnace or the like for increasing the moisture content of the air being heated thereby, comprising a mounting plate adapted to be secured over an aperture in the Wall of the furnace, a drive assembly mounted on one side of said plate and having a pair of coaxial drive shafts extending through an aperture in said plate to the opposite side thereof, one of said drive shafts being driven at a speed substantially slower than the other drive shaft, an evaporator drum mounted on said one shaft on the opposite side of said mounting plate, said drum having open and closed ends and including a resilient and porous evaporator material which defines the side walls of said drum, a reservoir on said opposite side of said mounting plate for enclosing the lower portion of said drum, means for maintaining a predetermined water level in said reservoir to Wet said evaporator material when said drum is rotated by said drive assembly, said other drive shaft having a portion extending axially beyond said one drive shaft, and air moving means mounted on said portion of said drive shaft for inducing air flow over the surfaces of said evaporator material to increase the humidity of the air.

4. A humidifier for adding moisture to air being treated by an air conditioning device, comprising a mounting plate adapted to be secured on a wall of the air conditioning device, said mounting plate having upper and lower separable sections, a drive assembly mounted on one side of said upper section and having a pair of coaxial drive shafts extending through an aperture in said upper section to the opposite side thereof, one of said drive shafts being driven at a speed substantially slower than the other drive shaft, an evaporator drum mounted on said one shaft on the opposite side of said mounting plate, said drum having open and closed ends and including a resilient and porous evaporator material which defines the side walls of said drum, means on the opposite side of said lower section defining a reservoir for enclosing the lower portion of said drum, means for maintaining a predetermined water level in said reservoir to Wet said evaporator material when said drum is rotated by said drive assembly, said other drive shaft having a portion extending axially beyond said one drive shaft, and air moving means mounted on said portion of said drive shaft coaxial with and substantially entirely within said drum for forcing air axially through said open end and radially through said evaporator material to increase the humidity of the air.

5. A humidifier for adding moisture to air being treated by an air conditioning device, comprising mounting means adapted to be secured on a wall of the air conditioning device, said mounting means including upper and lower rectangular plates adapted to be connected releasably along horizontal edges thereof, a drive assembly mounted on one side of said upper plate and having a pair of coaxial drive shafts extending through an aperture in said upper plate to the opposite side thereof, one of said drive shafts being driven at a speed substantially slower than the other drive shaft, an evaporator drum mounted on said one shaft on the opposite side of said upper plate, said drum having open and closed ends and an evaporator material which defines the side walls of said drum, means defining a reservoir on the opposite side of said lower plate for enclosing the lower portion of said drum when said upper and lower plates are secured together, means on said one side of said lower plate for maintaining a predetermined water level in said reservoir to wet said evaporator material when said drum is rotated by said drive assembly, said other drive shaft having a portion extending axially beyond said one drive shaft, and air moving means on said portion of said other drive shaft coaxial with and substantially entirely within said drum for drawing air axially through said open end and forcing it radially through said evaporator material.

6. A humidifier for adding moisture to air being treated by an air conditioning device, comprising a mounting plate adapted to be secured on a Wall of the air conditioning device, a speed reduction unit mounted on one side of said plate, a tubular output shaft rotatably supported in said unit, a motor mounted on said speed reduction unit and having its drive shaft extending through said unit Wit said drive shaft being concentric with said tubular shaft, means operatively connecting said unit to said drive shaft for rotation of said tubular shaft at a speed substantially slower than said drive shaft, said shafts extending through said mounting plate to the opposite side thereof, an evaporator drum mounted on said tubular shaft on the opposite side of said plate, said drum having open and closed ends and including a resilient and porous evaporator material which defines the side walls thereof, means defining a reservoir on the said opposite side of said mounting plate for enclosing the lower portion of said drum, means for maintaining a predetermined water level in said reservoir to wet said evaporator material as said drum is rotated, said drive shaft having a portion extending axially beyond said tubular shaft and internally of said drum, and air moving means mounted on said portion of said drive shaft coaxial with and substantially entirely within said drum for drawing air axially through said open end and forcing it radially through said evaporator material to evaporate at least a portion of the water from said material and increase the humidity of the air.

7. A humidifier for adding moisture to air being treated by an air conditioning device, comprising a mounting plate adapted to be secured on a wall of the air conditioning device, a speed reduction unit mounted on one side of said plate, a tubular output shaft rotatably supported in said unit, a motor mounted on said speed reduction unit and having its drive shaft extending through said unit with said drive shaft concentric with said tubular shaft, means operatively connecting said unit and said drive shaft for rotation of said tubular shaft at a speed substantially slower than said drive shaft, said shafts extending through said plate to the opposite side thereof, an evaporator drum mounted on said tubular shaft on the opposite side of said plate, said drum having a resilient and porous evaporator material Which defines the side walls thereof, means defining a reservoir on the said opposite side of said mounting plate for enclosing the lower portion of said drum, means for maintaining a predetermined water level in said reservoir to wet said evaporator material as said drum is rotated, said drive shaft having a portion extending axially beyond said tubular shaft internally of said drum, and air moving means mounted on said portion of said drive shaft for forcing air over the surface of said 9 evaporator material to evaporate moisture thereon and increase the humidity of the air.

8. A humidifier for adding moisture to air being treated by an conditioning device, comprising a mounting plate adapted to be secured on a wall of the air conditioning device, said plate including upper and lower separable sections, a speed reduction unit mounted on one side of said upper section, a tubular output shaft rotatably supported by said unit, a motor mounted on said speed redue-tion unit and having its drive shaft extending through said unit concentric with said tubular shaft, means operatively connecting said unit and said drive shaft for rotation of said tubular shaft at a speed substantially slower than said drive shaft, said shafts extending through an opening in said upper section to the opposite side thereof, said drive shaft having a portion extending axially beyond the end of said tubular shaft, evaporator drum means mounted on said tubular shaft on said opposite side of said mounting plate, said drum means having an evaporator material which defines the side walls thereof, means defining a reservoir on said lower section below said drum means for enclosing the lower portion of said drum means, means for maintaining a predetermined water level in said reservoir to wet said evaporator material as said drum means is rotated, and air moving means mounted on said portion of said drive shaft for inducing air flow over the surfaces of said evaporator material to evaporate at least a portion of the water on said surfaces and increase the humidity of the air.

9. A humidifier for adding moisture to air being treated by an air conditioning device, comprising a mounting plate adapted to be secured on a wall of the air conditioning device, a drive assembly mounted on one side of said plate and having a pair of coaxial drive shafts extending through an aperture in said plate to the opposite side thereof, one of said drive shafts being driven at a speed substantially slower than the other drive shaft, an evaporator drurn mounted on said one shaft on the opposite side of said mounting plate, said drum having open and closed ends and a resilient and porous evaporator material which defines the side wall of said drum, a reservoir on said opposite side of said mounting plate for enclosing the lower portion of said drum, means for maintaining a predetermined Water level in said reservoir to wet said evaporator material when said drum is rotated by said drive assembly, said other drive shaft having a portion extending axially beyond said one drive shaft, and air moving means including a disk having an outer diameter less than the inner diameter of said drum and being secured to said portion of said other drive shaft with one side adjacent said closed end of said drum, the opposite side of said disk being convex and having thereon a plurality of air flow inducing blades of triangular configuration each including a base portion rigidly secured to said convex side in radially extending relationship and a blade portion being smoothly curved in the direction of rotation of said disk for cooperation with said convex side to draw air axially through said open end and force it radially through said evaporator material to increase the moisture content of the air.

10. A humidifier for adding moisture to air being treated by an air conditioning device, comprising a mounting plate adapted to be secured on a wall of the air conditioning device, a speed reduction unit mounted on one side of said plate and having a tubular output shaft rotatably supported therein, a motor mounted on said speed reduction unit and having its drive shaft extending therethrough with said drive shaft concentric with said tubular shaft, means operatively connecting said unit and said drive shaft for rotation of said tubular shaft at a speed substantially slower than said drive shaft, said shafts extending through said plate to the opposite side thereof, an evaporator drum assembly including a back plate having a hub centrally disposed thereon for mounting said back plate on said tubular shaft, a plurality of brackets extending axially from the outer periphery of said back plate, a sleeve of highly porous material disposed on said brackets to form the sides of said drum assembly with said brackets offering substantially no interference to the flow of air through said sleeve, a reservoir on said opposite side of said plate for enclosing the lower portion of said drum, means for maintaining a predetermined water level in said reservoir to wet said evaporator material as said drum is rotated, said drive shaft having a portion extending axially beyond said tubular shaft internally of said drum, and air moving means mounted on said portion of said drive shaft coaxial with and substantially entirely within said drum for drawing air axially through the open end of said drive assembly and forcing it radially through said evaporator material.

11. A humidifier for adding moisture to air being treated by an air conditioning device, comprising a mounting plate adapted to be secured on a Wall of the air conditioning device, a drive assembly mounted on one side of said plate and having a pair of coaxial drive shafts extending through an aperture in said plate to the opposite side thereof, one of said drive shafts being driven at a speed substantially slower than the other of said drive shafts, an evaporator drum having an open end and including a back plate having a hub centrally disposed thereon for mounting said plate on said one of said drive shafts, a plurality of brackets extending axially from the outer periphery of said back plate, a sleeve of porous material disposed on said brackets to form the sides of said drum with said brackets offering substantially no interference to the flow of air through said sleeve, a reservoir on said opposite side of said plate for enclosing the lower portion of said drum, means for maintaining a predetermined water level in said reservoir to wet said evaporator material as said drum is rotated, said other of said drive shafts having a portion extending axially beyond said one drive shaft, and air moving means mounted on said portion coaxial with and substantially entirely within said drum for forcing air axially through the open end of said drum and radially through said evaporator material to increase the humidity of such air.

12. A compact humidifier unit adapted to be mounted on the wall of a hot air furnace or the like for increasing the moisture content of the air being heated thereby, comprising a mounting plate adapted to be removably secured over an aperture in the wall of the furnace, a drive assembly mounted on one side of said plate and having a pair of coaxial drive shafts extending through an aperture in said plate to the opposite side thereof, one of said drive shafts being driven at a speed substantially slower than the other of said drive shafts, evaporator drum means mounted on said one of said drive shafts on the opposite side of said plate, said drum means including evaporator material for adding moisture to the air, said drum means having an open end, means on said opposite side of said plate for wetting the surfaces of said material as said drum means is rotated, said other of said drive shafts having a portion extending axially beyond said one of said drive shafts, and air moving means mounted on said portion of said other of said drive shafts for drawing air axially through said open end and forcing it over the surfaces of said evaporator material.

13. A humidifier for adding moisture to air being treated by an air treating device, comprising mounting means adapted to be secured on a Wall of the air treat ing device, said mounting means including upper and lower plates adapted to be releasably interconnected, a drive assembly mounted on one side of said upper plate and having a pair of coaxial drive shafts extending through an opening in said upper plate to the opposite side thereof, one of said drive shafts being driven at a speed substantially slower than the other drive shaft, evaporator drummeans mounted on said one shaft on the opposite side of said upper plate, said evaporator means including highly porous evaporator material which defines the side walls of said drum means, means defining a reservoir on the opposite side of said lower plate for enclosing the lower portion of said evaporator drum means when said upper and lower plates are secured together, means associated with said reservoir for maintaining a predetermined water level in said reservoir to wet said evaporator means when said drum means is rotated by said drive assembly, said other drive shaft having a portion extending axially beyond said one drive shaft, and air moving means on said portion of said other drive shaft for forcing air through said evapo rator means.

14. A humidifier unit as defined in claim 13 wherein said means associated with said reservoir is a chamber on said one side having a float control valve associated there'- with to maintain a predetermined water level therein, and

means defining a passage connecting said chamber and said reservoir so that the water level in said reservoir is controlled by said predetermined level in said chamber.

References Cited in the file of this patent UNITED STATES PATENTS Decker Oct. 6, 1931 Simpson July 23, 1940 Alquire Feb. 18, 1941 Robic Apr. 8, 1941 Stratton June 23, 1942 Wiesenthal Apr. 10, 1951 Bailey Mar. 10, 1953 Geen Jan. 3, 1961 Byrge Feb. 20, 1962 Sevald Jan. 22, 1963 FOREIGN PATENTS Italy Feb. 11, 1938 France Nov. 17, 1958 

12. A COMPACT HUMIDIFIER UNIT ADAPTED TO BE MOUNTED ON THE WALL OF A HOT AIR FURNACE OR THE LIKE FOR INCREASING THE MOISTURE CONTENT OF THE AIR BEING HEATED THEREBY, COMPRISING A MOUNTING PLATE ADAPTED TO BE REMOVABLY SECURED OVER AN APERTURE IN THE WALL OF THE FURNACE, A DRIVE ASSEMBLY MOUNTED ON ONE SIDE OF SAID PLATE AND HAVING A PAIR OF COAXIAL DRIVE SHAFTS EXTENDING THROUGH AN APERTURE IN SAID PLATE TO THE OPPOSITE SIDE THEREOF, ONE OF SAID DRIVE SHAFTS BEING DRIVEN AT A SPEED SUBSTANTIALLY SLOWER THAN THE OTHER OF SAID DRIVE SHAFTS, EVAPORATOR DRUM MEANS MOUNTED ON SAID ONE OF SAID DRIVE SHAFTS ON THE OPPOSITE SIDE OF SAID PLATE, SAID DRUM MEANS INCLUDING EVAPORATOR MATERIAL FOR ADDING MOISTURE TO THE AIR, SAID DRUM MEANS HAVING AN OPEN END, MEANS ON SAID OPPOSITE SIDE OF SAID PLATE FOR WETTING THE SURFACES OF SAID MATERIAL AS SAID DRUM MEANS IS ROTATED, SAID OTHER OF SAID DRIVE SHAFTS HAVING A PORTION EXTENDING AXIALLY BEYOND SAID ONE OF SAID DRIVE SHAFTS, AND AIR MOVING MEANS MOUNTED ON SAID PORTION OF SAID OTHER OPEN END AND FORCING IT OVER THE SURFACES OF SAID EVAPORATOR MATERIAL. 